The invention is based on a device for automatically switching lighting devices in vehicles.
One such device is known from German Patent Disclosure DE 195 23 262 A1. This device has a sensor device, which detects the light intensity in the surroundings of the vehicle. The sensor device has at least one global sensor, which nondirectionally detects the general light intensity in the surroundings of the vehicle. The sensor device also has a directional sensor, by which the light intensity is detected directionally in the travel direction ahead of the vehicle. An evaluation device is connected to the sensor device, and by means of the evaluation device the signals of the global sensor and the directional sensor of the sensor device are compared with threshold values; if at least one threshold value or both threshold values is undershot, the lighting devices are switched on. By means of the signals of the global sensor, it can be assured that the lighting devices will be turned on as dusk becomes general, and by the signals of the directional sensor, it can be assured that the lighting devices will be turned on before entering a tunnel, for instance. It has been found that with this known device, reliable activation of the lighting devices cannot be achieved under all circumstances, for instance because of a temperature dependency of the sensor device signals.
The device of the invention for automatically switching lighting devices in vehicles has the advantage over the prior art that even at different temperatures, reliable switching of the lighting devices is achieved.
Upon abrupt changes in brightness, which are problematic in terms of the adaptation of the human eye, it is possible to turn the lighting devices on even at relatively great brightness, thus improving visual conditions. Turning on the lighting devices will occur after a certain travel distance of the vehicle, for instance in good time before entering a tunnel. The switching of the lighting devices can be adapted to weather conditions; if precipitation is present, they are already turned on at greater brightness than under dry conditions. The lighting devices are switched on at greater brightness when the intensity of the precipitation is increasing.